You can use the CSV Extended format with something like PyMISP, e.g., for each indicator type you want to bring in run a scheduled job:
/python3 /home/user/misp_api/get_csv.py -f /home/user/misp_logs/ip-dst.log -t "ip-dst" -l 1d -c
And then use a Chronicle Forwarder, NXLog, or other agent to ingest into Chronicle SIEM. This will work with the default MISP_IOC parser.
I wrote this enhanced version of the Ingestion Script (from the SIEM GitHub repo) which is a bit more involved to setup, but is more flexible and extracts more fields:
https://github.com/goog-cmmartin/thatsiemguy/tree/main/misp